Scute: for infection, inflammation, and protection
Scute is the common name selected 35 years ago by the Oriental Healing Arts Institute as a shortened version of the genus name for the source material of huangqin, which is the root of Scutellaria baicalensis (Baikal skullcap). The plant naturally occurs in northern China (especially Mongolia), northern India, Korea, Japan, and Russia; it is also cultivated, primarily in China. This is a commonly used herb, and it is distinguished from another, far less frequently used Chinese herb from the same genus: the whole plant of Scutellaria barbata (banzhilian) that is often administered for treating “toxic” syndromes, including snake bite and cancer (1). These two East Asian species differ from the western skullcap, Scutellaria lateriflora, naturally occurring in North America, with the tops used as a sedative herb.
Scute is classified in the Chinese Materia Medica guides as one of the herbs for clearing heat and drying dampness. Although the Materia Medica has a very large section of heat clearing herbs, this particular subdivision incorporating “drying dampness” has few materials. The herbs placed in this subsection are especially known for their potential in treating diarrhea and dysentery, sore throat, hot-type cough, skin diseases, and jaundice; and it is this group of “damp-heat” disorders that are the basis for the particular classification of the herbs. Only five of them are frequently used: scute, coptis (huanglian), phellodendron (huangbai), sophora (kushen), and gentiana (longdancao).
While scute has a potent medicinal value, especially for inhibiting infections and reducing inflammation, both the herb and its isolated active components are virtually free from side-effects. It is usually indicated for use in modest dosage (e.g., 5-10 grams/day in decoction) in complex formulations, but can be used in higher doses (e.g., 12 grams per day routinely recommended in formulas for eczema and 15 grams per day for common cold). Oriental Materia Medica (2) indicates a dosage of 6–15 grams per day, with a dose of 1.5–5 grams per day for “children under two years of age.” The isolated ingredients have been administered in substantial quantities. A 250 mg tablet of the main flavone, baicalin, is available in China and used to treat viral hepatitis at a dose of two tablets, three times per day, for a total dose of 1500 mg (3). This quantity is comparable to high dosage administration of flavonoids from other plants, such as rutin and quercetin.
The taste of scute is slightly bitter, not nearly as bitter as the other substances in this Materia Medica category. Sophora is designated “ku” meaning bitter; gentiana is designated as “longdan,” meaning bile of the dragon, because it is so extremely bitter; coptis and phellodendron, though not named for their bitter qualities, are known for their extreme taste. Unlike coptis, phellodendron, and sophora, which rely on alkaloids for their effects, scute is free of alkaloids and has, instead, a large number (about 50 identified thus far) of flavones and flavone derivatives (4). Flavonoids as a group are low in toxicity. In Pharmacology and Applications of Chinese Materia Medica (5), the description under the heading adverse effects is: “According to clinical experience, huangqin has a low toxicity. No ill effects except rare gastric discomfort and diarrhea, were associated with either oral administration of the crude preparation of huangqin, or injection of bacalin and baicalein.”
An examination of the reported historical uses of scute (6) conveys a sense of mildness and safety. Scute is said to: “equalize the vital principles, to be tonic to the bladder, quieting to the pregnant uterus, stimulant to the respiratory organs, anodyne, and astringent.” The herb is traditionally contraindicated for use in persons with coldness and deficiency of the stomach that causes loss of appetite or loose stool (7). Among the clinical applications mentioned for the herb, alone or in simple combinations, were: respiratory tract infection in children; chronic bronchitis; scarlet fever; bacillary dysentery; leptospirosis; infectious hepatitis; acute biliary tract infection; and hypertension. The use for leptospirosis is of interest to some in the West today because this bacterial organism is of the same group, the spirochetes, as the one that causes Lyme Disease. The treatment with scute described for leptospirosis is the formula Shuang Huang Lian (8), which is comprised of scute, lonicera (jinyinhua), and forsythia (lianqiao).
Scute has been included in formulations for prevention of liver fibrosis secondary to viral hepatitis, mainly in Xiao Chaihu Tang (Japanese name: Shosaiko-To; English:Minor Bupleurum Combination) or its variants. This formula, and the active components baicalein and baicalin from the ingredient scute, have been demonstrated in a few laboratory studies to reduce stellate cell activation and proliferation, which is a major cause of liver fibrosis, possibly accomplished by regulating cytokines (9).
In Combination with Other Herbs
One of the well-known traditional prescriptions with scute is Huang Lian Jie Du Tang (common name: Coptis and Scute Combination). The formula has four yellow-colored herbs: coptis, phellodendron, gardenia (shanzhizi), and scute, which are all used for clearing heat and drying dampness (gardenia is placed in a different category of the Materia Medica, but is often used for damp-heat). Coptis and phellodendron contain yellow-colored protoberberine alkaloids; gardenia contains red-yellow iridoid glycosides, and scute contains yellow flavones. This simple formulation is used for alleviating “heat in all three burners” of the sanjiao (triple burner) system, which is a TCM-defined organ system involving the transport and management of both heat and moisture. As an indication for use of this formula, in addition to having heat in all three burners, the heat is also likely to be in all three “layers” (or “aspects”), namely the layer of qi, the layer of ying (nutrient), and the layer of blood. These four herbs together can inhibit infections that are often at the root of such damp-heat syndromes, and have several symptom-alleviating effects, such as calming mental agitation and insomnia, reducing inflammation, and controlling bleeding (when the loss of blood is secondary to infection and inflammation, as occurs with intestinal or urinary bleeding). There are many variants of this formulation, usually utilizing coptis and scute as the base pair taken together with a few other herbs that address a specific concern. For example, in many of the hot type diseases, rhubarb is incorporated to purge the gallbladder and intestines. This purgative action is a traditional means of draining excess heat, a method of therapy which is still being used in modern China (10).
For cases of bleeding due to heat in the blood, scute is a common ingredient in formulas made as pills. A good example is the traditional Huai Jiao Wan (Pills of Sophora Fruit), which contain six ingredients for inhibiting bleeding, the formula indicated for intestinal bleeding (11).
Scute as a single herb is recommended in the form of a tea (Huangqin Cha) at a dose of 15 grams per day for treatment of acute conjunctivitis (12). When used in complex formulas, the role of scute is often to resolve heat rather than to specifically address damp-heat. The following is an example of herb combining principles relayed by Qin Bowei (13):
For binding heat in the qi aspect, scute is coupled with bupleurum (chaihu); for binding heat in the blood aspect, scute is coupled with peony (baishaoyao). Bupleurum is capable of opening the bondage in the qi aspect, but cannot clear the heat in the qi aspect. Peony is capable of opening the bondage of the blood aspect, but it is unable to clear heat of the blood aspect.
Scute Active Components
The chemical constituents of scute have been extensively analyzed and involve flavone and flavone derivatives. Many of the flavones are present in the glycoside form (sugar molecule attached to the basic flavone) as the dominant component, with lesser amounts of the aglycone. The flavones make up as much as 20% of the root. Baicalin (the glycoside form, illustrated here) and baicalein, the aglycone, dominate, comprising about 12% of the root; wogonoside (the glycoside form) and wogonin make up about 4% of the root; another 4% is contributed by dozens of flavones present in small quantities (14). The flavones are most readily extracted in an ethanol-water solution, and concentrates having 95% flavone content are commercially available.
One preparation using this 95% extract, called Baicalcumin, was introduced in the U.S. by ITM nearly 20 years ago, with recommended doses of 4-12 tablets per day, providing 800–2,400 mg of the 95% flavone extract, which might be used for antiviral and anti-inflammatory activity. Adverse responses were not reported. An anti-inflammatory herbal compound for prescription use indicated for osteoarthritis is called Limbrel (flavoxid); it is comprised of flavonoids from scute and from catechu (ercha). Limbrel is suggested to be given in doses of 250 mg each time, twice daily, for a total of 500 mg per day. In the treatment of psoriasis a combination of 450 mg baicalin three times daily (total daily dose is 1,350 mg) with an equal amount of concentrated extract of rhubarb was utilized in Chinese clinical work and appeared to be effective for some patients (15).
Pharmacology studies (16) indicate that scute and its flavone compounds are inhibitors of bacteria and viruses, including staphylococci, cholera, dysentery, pneumococci, and influenza virus; baicalin and baicalein are potent anti-inflammatory and anti-tumor agents, free radical scavengers, and xanthine oxidase inhibitors (thus conferring cardiovascular protective actions). Neuroprotective action has also been indicated by recent work (17).
Samples of non-prescription products: capsules containing only scute, left; and a tea (indicated for allergies) made of scute plus arctium (niubangzi), right.